Ruler



FIG. 1 is a front, left, top perspective view thereof;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a left side view thereof; and,

FIG. 7 is a right side view thereof.

Dotted lines indicate the area where a keypad, LCD and solar panel would be located and are not claimed in this patent. 

The ornamental design for a ruler, as shown and described. 